MySQL：如果列不存在，如何添加？
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时间：2020-08-31 16:32:48 来源:igfitidea点击:
MySQL: How to add a column if it doesn't already exist?
提问by Andrew
I want to add a column to a table, but I don't want it to fail if it has already been added to the table. How can I achieve this?
我想向表中添加一列，但如果它已经添加到表中，我不希望它失败。我怎样才能做到这一点？
# Add column fails if it already exists
ALTER TABLE `TableName` ADD `ColumnName` int(1) NOT NULL default '0';
回答by OMG Ponies
Use the following in a stored procedure:
在存储过程中使用以下内容：
IF NOT EXISTS( SELECT NULL
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'tablename'
AND table_schema = 'db_name'
AND column_name = 'columnname') THEN
ALTER TABLE `TableName` ADD `ColumnName` int(1) NOT NULL default '0';
END IF;
Reference:
参考：
